Method of manufacturing pipe nipples or the like



g- 1949- R. J. FRETER 2,480,011

METHOD OF MANUFACTURING PIPE NIPPLES OR THE LIKE Filed Nov. 7, 1945 IN V EN TOR.

RoyJ. Frerzr A TTUPNE Y5.

Patented Aug-23; .9;

" NIPPLES on THE LIKE Roy Freter, (lolumbusfohloyassignor to I iandis Machine Company, Waynesboro, Pa, a corporation of Pennsylvania Application November 7, .1945, s r al no; 627,186

4 Claims. (Cl. 29-156) My invention relates to the method of nianufacturing pipe nipples or the like. It has to do, more particularly, with extruding the metal at the ,end of the pipe, forming a taper onthe outer diameter ofthe pipe, forming a chamfer on the end of the outer diameter of the pipe, and forming a radius or chamfer at the inside diameter at the end of the pipe thereby preparing the pipe for rolling or grinding threads thereon.

In the past, the manufacture of pipe nipples has consisted of cutting to proper lengths, burring or chamfering, and then cutting the threads on each end of the pipe. In cutting of pipe nipples, a length of pipe is severed by cutters to the desired length and this cutting operation forms burrs or ragged edges on the inside periphery of each end of the pipe. At present, a burring tool is insorted into each end of the pipe nipple to cut away or chamfer the ragged edge or burr preparatory to the threading operation. When manufacturers have suitable equipment, the chamfering and threading operations may be combined by inserting a tapered reamer in the thread cutting head.

The function of a nipple is such that it requires a tapered thread controlled by certain prescribed limit tolerances which insures a tight, leak-proof fit when assembled in its mating parts. It is a recognized fact that cut threads cannot be controlled as easily as threads that are rolled or ground. Many factors enter into this, and one in particular is the usually prevalent rough and torn-threads characteristic to cut method. Pipe nipples are a low-cost production item, and the necessity of keeping production cost down prevented the feasibility in the past to roll or grind the threads due to the lack of suitable and proper available machinery.

To roll or grind a thread on the nipple, a tapering operation is required on the part to be threaded. To grind or cut this material away preparatory to thread rolling or thread grinding, needv less to say, would considerably increase the cost of production. This costly operation has been replaced by an extruding or sizing operation where,- by the taper, chamfer, and radius are produced simultaneously and economically.

The use of pipe nipples is very extensive, and it is necessary to keep the cost of these to a minimum but at the same time producing a quality product.

One of the objects of my invention is to provide I a pipe nipple which has both of its ends formed by an extruding method whereby the pipe taper on the outer diameter can be formed, the ends of the pipe chamfered on -the outer diameter and the radius'at its ends on internal diameter be formed. t-

Another object of my invention is to provide a method and apparatus for chamfering, radiusing and tapering ends of a pipe nipple by extruding or sizing which strengthens the metal and at the same time lengthens'the same.

Another object of my invention is that I provide a method for tapering the outside walls of the pipe nipple while maintaining the inside diameter of the nipple constant.

Another object of my invention is to provide a pipe nipple which can be t'apered, chamfered, and radiused efliciently so that said end portions can be threaded efliciently by means of the rolled or ground methods, thus roducing a higher quality, but cheaper, nipple.

Another object of my invention is to provide a method and apparatus for preparing pipe nipples for threading operations at greatly reduced cost and .with a, great savings in time.

Various other objects and advantages will be apparent from the drawings and the following detailed description wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a side elevational view of a length of pipe showing cutters applied thereto for cutting the pipe to the desired nipple length.

Figure 2 is a sectional view of a pipe cut to a nipple length with a burr formed thereon.

Figure 3 is an end view of Figure 2 showing more clearly the burr formed thereon.

Figure 4 is a side elevational view in section showing the die members for tapering the outer ends of the pipe and also the pins for removing the burr formed on the inner wall of the pipe. Figure 5 is a side elevational view in section showing the pipe after it has been tapered and burred for a subsequent thread grinding operation.

Figure 5a is a side elevational view, partially in section, showing the pipe after it has been prepared, according to my method, for a subsequent thread rolling operation.

Figure 6 is a side elevational view, partly in section, of the finished threaded nipple.

Referring to the drawings, more particularly to Figure 1, I show a length of pipe i which is adapted to be cut into desired lengths by means of cutters 2 of the conventional type. This pipe cutting operation cuts the pipe into near nipple lengths 3. In cutting the pipe I by means of the cutters 2, a ragged edge or burr 4 is produced and formed on the inner end walls of the pipe.

" 'eaph end before a finished m me can bet p159;

isto remove theborrbychemfering eachend or V p the pipe afteig it heebeen cuttoits proper length, i

or to e'ombine the operatioiiwheii out threading in some cases. Figures-2 andfis hbw theburr or caused by the cutting operation;

that is' formed on the innnend well of the pipe i I have found that the burring and damping of the-pipe can beaccomplished simuite neously atj each-end ofthe pipein one operetion'by using eitruding or sizing dies of the, desired sized To 2 accomplish the burring anditaperihe Of thepipe ni ple 3 preparatory tothe threading dperetipns,

Iwpro vide tapered die membersi'and mounted within the housing or holders 1 and ,la. The p housings I, andla arepxt'ovided with-pins Send In.

whose inner end's' are reduced as'et land flahnd i whieh areedapted tofitv within each. end Vofbihe nipplel. The dies'i andi andthe hurling pins 9 and 9a may be usedon e press or reheader*-.

machine of-the conyentional type mownawny,

one another when the extruding operation is complete. The rounded shoulder LIB serves to remove the b11111 and round theedges; of the vided with a rdundedend poriion flb which per mitsqeasy'entryof the pin Qwithin the pipe 3.

The die Bis. similar to the die 5 and is provided with a. taperedportionfia and shoulder 61: similar.

The diefipis tapered asi at Smend providedwitlix; a shoulder 5b beco e together jwith the end i n the pipe 3 when the extruding vor sizing operation I is complete; The in 8,15 proyidedy with g.

rounded shoulder l Onthe bui ring pin portion 91* The shoulder b and theehoulder l0 align with thread depthldlherefore, theblehk 3a,as pre-'- i pared for thread'rolling, assumesrthe shape shown of, topically chafntered portions at 0115 to the shoulderib ofithe die '5. The die 8 is further provided with a straight portion lid that is edaptedtohold the pipe sr pgly gherein The; pin 8a is provided with a mended-qr radiused boulder 10d and fa burringrpin 9a haYllflgWB twoidie members 5 andfi togethen yThe burying n The operetions of bu -m and tapering, pipe 3 are 'earried' oi t by-inserting 'the pipe within: the'die member 6 and then bringing the pipe 3 and remove the \burrs A, and t the same I mime; these T'pins act an inner support. for the pipe 3 as the tapered die portions Saend Gabegin -to aqt on theouterwall Ofwthe pipe. During the extrusion iprocess thepins 9 am 9d prevenplthe a ipe 3 from, collapsing 01 distorting as the dies "are pressed together. The pressing action cons ti'nues until the shoulders Strand 6b align with ,n the shoulders and Illa respectively, thus form:

mg the taper "and the chamf ered' edge oi the] ,pipe. The dies Bend darethen moved apart permittingthe pipe 33:0 be ejected from the dies I 4 i 5i and B by means of the knockout; pins 8" and 8a., A stripper mechanism (mp shown) staripsnipple pins'being withdrawn intowdies 5 and B;

" It will benoted that the lengt oilthedie sis};

the pipe while the length of the diets is the length ofthe tapered portion piu s the [intermediate this variation "in the shapes of the dies isto do A the on n d e hu prevent bucklin Thepipenippleshownin Figure 5 wieh its ta axis of the pipeiffThe portionslfic are preferably formed at an angle of 30f withthe axis ofthe pipe. However, these figure s are nofiwcriticel since th enly obieet ofw ihe additional portions Seand 1 lb (so prdviderobni for the flow of the liiiialgglufing thefthijeald rpll iifig operatipn V d 1 he nk pnle Show? Tinr f i Dreduped 'in g manner'i identifial with" that desc ihedi above for producing the blankshown in F'igure 5.

11; is nie 'eiy necesseryftoj iorm dies '5 and 6 a -;nan1ier which willeeuse them to p oduee the ad:

ditipnai's rfaeesfic 91nd lb, 1 Theffdie tance from eithee 2 end oi blank All to the beginning, of the portion I lbsholildbe medef equel to the desired effective, thread length of the resulting nippleq In Figure 6, I show afinishedmppleSwhihhas beeri rolled or bgrognd ithrea dedj on the article shown in Figure 5. Rolling andgrinding threads llon nipple greatl i maroves them over the p esent-day out thread nipples. Besides" the fact that; the threads are nione uniform, experience in rolling pend" grinding threads has proven that it inereases tlie desi red physical properties of the steel andizhereby makes a strongefps noother and better thread- The thread I2, shownon the nipple Mn Figure 6, e precision job whiehgean now bepsed eppipe nipplesdue to the sizing and bu 'ing operations diseu ssed abovef The taper 1 ing of th'e endsotfthe ,pipe at; onetime; hwhich has heretofore been prohibitive in e 'tioi-es of this type, canbequickl andeheaply accomplished by my pered end'portions :lfl een beerolle'd (or ground thi eaded, or, it desiied, cenbe duh therei I- h9 di e 1pn1eisetter itrhas been exmmewapa bim ed ao'oording to myzpm i ess sbfthat it is irisuitable conditionifm" asubsequen'ti threeding operation The tapered ende Here unifo m afid thej'portionsewhich havebeen i lhur're'dby pines arid aa aremuchsmoother than p canbe eecomplished-onithepresent dey boning devices. In the. one operation, Lteper the ends of the date: end'wallsfl I of thepipe lend simple teneously remove theyburrjl from the inner] peripherythereof; 'Ihehpipehaselsobeeri elon geted and workhafdex ed "by the extrusion proc esseo thtesxpaller length pipeoan be used to obtainthe, prope -length nipple. A great saving i "can bem ealized inii neterial elongating the; nipple isinflqe if, malp'ioduction iteiiiw U It be understood that; certain difieren'oes exist between such blanks as pi epared for (a sub; sequem; grinding operation (and those" prepared fdl a subsequent thread rolling opez ation'. -An exainple of the iabheif is shown in FigurefiafiAs' is-wel1knowii in the gi t of=-threed;i7o1lihg, the diameter offithe blank to bev threededmustbe less thariiphat of thedesired wfinished threadby' inFigure Sa, heving thetapered portionsxl la at] each end thereof; a second minor conieal transi- .4tionportions ilb between tapered portions H and thestraighteentral portion, ands, third, pair t r mi ies thereof; The portionswllb preferably] make an angle of approximately 59 with the on. If this last-named operation is preferred, it can be accomplished much easier than presentday cutting operations since it is not necessary for the cutting chasers to remove excess material to taper the nipple as it cuts the thread. I have described a process for preparing a nipp e for a threading operation of any type whatsoever. Primarily, however, the nipple which I have prepared makes possible the use of rolled or ground threading operations which are preferred over cut threads. Threads which are rolled or ground will stand a great deal more tightening and loosening of the pipe at a joint and are not easily destroyed by repeated operations of this type, together with the advantage of a smooth, uniform thread.

I do not show in the drawing any means, for

rolling or grinding the threads since machines of this type are in use, and I do not claim any novelty in the forming of threads but only in the preparing of the nipple for the threading operation as set out above. Any type of machine can be used for grinding or rolling these nipples which can be used on hollow articles.

Variousother advantages will be apparent from the above description, the drawings, and the following claims.

Having thus described my invention, what I claim is:

1. A method of forming pipe nipples comprising the steps of cutting a section of predetermined length from a piece of pipe, the cutting operation reducing the internal diameter at the ends of said section; simultaneously applying uniformly expanding cold-forming forces throughout the entire internal circumference of the end portions of said section to restore the original internal diameter of the section and applying uniformly contracting cold forming forces around the entire circumference of such end portions to impart frusto-conical shape thereto; and then roll-threading the frusto-conical end portions.

2. A method of cold-forming pipe nipples comprising the steps of cutting a section of predetermined length from a piece of pipe, the cutting operation reducing the internal diameter at the ends of said section; simultaneously forcing forming instrumentalities into and onto the ends of said section to restore the original internal diameter thereof, to form internal chamfers at the ends and to apply circumferential reducing forces to the ends of said section to impart frusto-conical shape thereto; and then roll-threading said frusto-conical portions.

3. The method of cold-forming a pipe nipple consisting of the steps of cutting a section of predetermined length from a piece of pipe, the cutting operation reducing the internal diameter of the ends of said section; simultaneously applying internal expanding and external contracting forces throughout the full internal and external circumferences, respectively, of the end portions of the section, by forcing forming instrumentalities into and onto such end portions of the section, to restore the original internal'diameter of said section, to form internal and external chamfers at the ends thereof and to impart frustoconical external shape to the end portions; and then roll-threading the frusto-conical end portions.

4. The method of cold-forming a pipe nipple consisting of the steps of cutting a section of predetermined length from a piece of pipe, the cutting operation reducing the internal diameter of the ends of said section; supporting the intermediate portion of said section to prevent expansion thereof; simultaneously applying internal expanding and external contracting forces throughout the full internal and external circumferences, respectively, of the end portions of the section; by forcing forming instrumentalities into and onto such end portions of the section, to restore the original internal diameter of said section, to form internal and external chamfers at the ends thereof and to impart frusto-conical external shape to the end portions; and then roll-threading the frusto-conical end portions.

ROY J. FRETER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,276,013 Beach Aug. 20, 1918 1,504,764 Johnson Aug. 12, 1924 1,618,541 Lang Feb. 22, 1927 1,751,448 Campbell Mar. 18, 1930 1,930,745 Fisher Oct. 17, 1933 2,089,784 Cornell Aug. 10, 1937 2,176,993 Gazey Oct. 24, 1939 2,217,194 Bryce Oct. 8, 1940 2,325,480 Crawford July 27, 1943 

